Drill stem cleaner

ABSTRACT

Apparatus for cleaning interior walls of a sectionalized drill stem of a rotary drill, the drill having a rotating drilling head to which sections of a drill stem can be secured, the apparatus having a scraper having a sliding fit in a clean drill stem and secured by a cable from the drilling head so that when, during a drilling operation, the drill head is disconnected from an upper end of the drill stem and lifted to add a new drill stem section the scraper is automatically drawn upwards through the upper section of the drill stem so as to scrape the walls of the latter.

United States Patent 11 1 1 1111 3,

Hall June 26, 1973 [54] DRILL STEM CLEANER FOREIGN PATENTS 0R APPLICATIONS Inventor: James Hall, 405-1275 Ham 18,249 9/1905 Great Britain 15/1043 Street, Vancouver, British Columbia Canada Primary Examiner-Leon G. Machlin 22 Fil d; July 2, 1971 Attorney-Brian J. Wood 21 Appl. No.: 159,168

[ ABSTRACT Apparatus for cleaning interior walls of a sectionalized S 15/104'l6 166/ 25 1 93: drill stem of a rotary drill, the drill having a rotating [58] Field of Search 15/104. 16, 104.05, dnnmg h-ead whlch seams be 15/104033 1043 104.8; 166/170 cured, the apparatus havmg a scraper having a slldmg fit in a clean drill stem and secured by a cable from the 73/4252 drilling head so that when, during a drilling operation,

[ 5 6] References Cited the drill head is disconnected from an upper end of the drill stem and lifted to add a new drill stem section the UNITED STATES PATENTS scraper is automatically drawn upwards through the 2,157,493 5/1939 Miller et a1. 15/243 upper section of the drill stem so as to scrape the walls 2,149,810 3/1939 Kliewer 15/l04.05 of the latter, 3,507,328 4/1970 Henderson. 166/170 2,826,077 3/1958 Walker 15 1043 x 4 Claims, 3 Drawing Figures DRILL STEM CLEANER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to apparatus for cleaning interior walls of a drill stern of a rotary drill during a drilling operation.

2. Prior Art The propensity of drill stems of rotary drills to become encrusted with rock chips, mud and the like to a point where passage of an overshot for lifting core tubes is hingered. This is especially so in rotary drills used in mining exploration where exploratory drilling is carried in soft rock, or coal, or where mud or sand is encountered.

During a drilling operation, it is common practice when adding a new section of drill stem, to examine the upper section of drill stern in the hole to ascertain whether or not the drill stem requires cleaning, a cleaning tool of type then being manually thrust into the stem to scrape the latter of any accumulation of rock chips and mud. This is arduous and time co nsuming and is sometimes not carried out resulting in overbuildup of incrustation.

SUMMARY OF THE INVENTION The present invention provides drill stem cleaning apparatus which automatically scrapes the walls of an upper section of a drill stem whenever a drilling head is disconnected from a drill stem to add new section of drill stem. I

The cleaning apparatus of the present invention furthermore does not require manual operation as it is drawn through the drill stem when the drill head is hoisted away from the drill stem. Failure to clean the drill stem, whether accidental or deliberate, is therefore avoided.

The cleaning apparatus of the present invention includes a substantially tubular scraper normally having a sliding fit in a clean drill stern section, a cable connecting the scraper and the drill head for suspending the scraper inside an upper drill stern section so that when the drill stem is disconnected and hoisted away from the upper section of the drill stem to add a new stem section the scraper is automatically pulled upwards through the upper section of the drill stem so as to clean the walls thereof.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a central sectional view of portion of a drill stem showing the cleaning apparatus of the invention inserted therein,

FIG. 2 is a section on 2-2 of FIG. 1,

FIG. 3 is a perspective view of a scraper, a portion thereof being moved for the purpose of clarity of illustration.

DETAILED DESCRIPTION I FIG. 1

FIG. 1 shows an upper portion of a sectionalized drill stem, generally 10, an upper section 10.1 of which is connected to a drill head 11, the latter being rotatably driven by conventional and well known means and which has a fluid passage 12opening at one end 13 into the drill stem through which drilling fluid is pumped by conventional and well known means. The fluid travels through the drill stem and is discharged through a drill bit, not shown, so as to carry rock chips and the like from the face of the drill hole and upwards where it is re-circulated through the drill head and into the drill stem.

Due to rotation of the drill stem during a drilling operation the rock chips, mud and the like in the recirculated drilling fluid, and which are normally heavier than the drilling fluid, are thrown radially outward and cling to the walls of the drill stem gradually building up a crust 15, the crust being relatively thick adjacent an upper end of upper section 10.1. If the crust is not removed effective inside diameter of the drill stem is so reduced as to materially hinder passage of an overshot for retrieving, in a known manner, a core tube.

Cleaning apparatus generally 18, as shown in FIG. 1, is connected to the drill head 11. The cleaning apparatus includes a cylindrical tubular scraper 19, see FIGS. 1, 2 and 3, having an outside diameter a little less than inside diameter of a drill stem so as to have a slidable fit therein. The scraper is bevelled at its upper end to provide a knife edge 22 and has a connecting bar 23 extending diametrically thereacross.

A cable 24 is looped at one end around the bar 23 and secured by clamps 25. The cable is also looped about and secured to a connecting bar 26 of the drilling head by clamps 27.

Length of cable is such that with the drilling head 1 1 secured to thedrill stem'section 10.1 the scraper is disposed just above the lower end 28 of the section 10.1.

A screen 2 9, see FIG. 1, is secured adjacent a lower end of the scraper. The screen has openings large enough to enable rock chips circulated with the drilling fluid to pass through the drill stem during a drilling operation.

OPERATION During a drilling operation the cleaning apparatus which is secured to the drilling head as herein described remains inside the upper drill stem section. Due to its tubular configuration it offers little resistance to the passage of drilling fluid therethrough.

When the drill stem has been advanced sufficiently to require addition of a new drill stem section the drilling head is detached from the upper drill stem section and hoisted. The scraper is thus moved upwards through the upper drill stem section 10.1 so as to scrape the walls thereof and remove the crust 15 which is retained on the screen 29 for disposal when the scraper is pulled clear of the drill stem section 10.1. The scraper is then inserted into the new drill stem section and drilling recommenced.

It is seen that cleaning of the drill stem is an automatic operation as the cleaning apparatus is never detached from the drill head so that the upper section of the drill stem is always cleaned when a new drill stem section is added.

I claim:

1. Cleaning apparatus for cleaning tubular drill stems of a rotary drill, the drill having a drill head adapted to be secured to an upper end of an uppermost drill stem section and having a fluid passage through which drilling fluid is pumped into the drill stem, the cleaning apparatus including:

a. a tubular scraping member adapted to have a slidable flt in the drill stem,

b. a cable secured at one end to the scraping member and at an opposite end to the drill head so that the 3. Apparatus as claimed in claim 1 in which length of the cable is such that when the drill head is connected to an uppermost drill stem section the scraping member is suspended above a lower end of the uppermost drill stem section.

4. Apparatus as claimed in .claim 1 in which the scraping member has a transverse connecting bar extending diametrically thereacross for securing the member to the cable. 

1. Cleaning apparatus for cleaning tubular drill stems of a rotary drill, the drill having a drill head adapted to be secured to an upper end of an uppermost drill stem section and having a fluid passage through which drilling fluid is pumped into the drill stem, the cleaning apparatus including: a. a tubular scraping member adapted to have a slidable fit in the drill stem, b. a cable secured at one end to the scraping member and at an opposite end to the drill head so that the scraping member is freely suspended in the drill stem and movable upwards therethrough to scrape the stem whenever the drill head is detached from an upper end of the drill stem to add a new drill stem section thereto, c. a screen secured to the scraping member for receiving material removed from the drill stem.
 2. Cleaning apparatus as claimed in claim 1 in which the scraping member is bevelled at an upper edge to provide a knife edge.
 3. Apparatus as claimed in claim 1 in which length of the cable is such that when the drill head is connected to an uppermost drill stem section the scraping member is suspended above a lower end of the uppermost drill stem section.
 4. Apparatus as claimed in claim 1 in which the scraping member has a transverse connecting bar extending diametrically thereacross for securing the member to the cable. 